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NickVil (Petroleum)
25 Aug 06 13:42
Hello!
I know that in an external floating roof tank, the minimum-size primary roof drain shall be capable of preventing the roof from accumulating a water level greater than design at the maximum rainfall rate. Normally this primary drain is placed in the central point of the roof and it can be a hose.
Also, the emergency drains are installed to keep water to a lesser volume that the roofs will safely support. Such emergency drains shall not allow the product to flow onto the roof.
If we have the primary roof drain, is it necessary to install those emergency drains? I think, the function is the same.
Regards
JoeTank (Structural)
25 Aug 06 17:30
They are not same thing. An emergency drain would come into play if the rainfall was extreme and to the point that the normal drains would not remove water quickly enough to prevent damage to the roof. Steve Braune 字串6
Tank Industry Consultants
www.tankindustry.com
IFRs (Petroleum)
25 Aug 06 21:51
Emergency drains are just open pipes sticking up from the ifr plate. They are essential to prevent the EFR from sinking if there is an extreme rain event or the main drain is blocked with debris or the tank valve on the end of the drain is closed, etc. They are inexpensive insurance and do not emit very much vapors.
JoeTank (Structural)
28 Aug 06 13:52
Never use an emergency drain on a single deck external floating roof such as a pontoon floating roof. Product could flow onto the roof during a flooded deck condition. Steve Braune
Tank Industry Consultants
www.tankindustry.com
NickVil (Petroleum)
4 Sep 06 11:54
Thanks for your comments. Related if the deck is simple or double, would you specify the standard that mention it? 字串2
I mean, single deck roofs shall not be fitted with emergency drains. And, in addition to normal roof drains, double deck roofs shall be fitted with emergency drains, capable of discharging rainfall in excess of design directly into the product.
Regards
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